Map 3.4 Master Plan of Hammarby Sjöstad, Stockholm

a mix of traditional inner-city perimeter blocks and open and contemporary urban zones. Inner-city street dimensions, block lengths, building heights, and densities are well harmonized and off er openness, sunlight, parks, and water views (map 3.4).

The area is also well connected to public tramlines. According to a 2005 survey, twothirds of all resident trips were made via public transportation, bicycles, and walking, and onethird by car (CABE 2009). Signifi cant public transportation ridership and bicycling and walking have helped to reduce car emissions and the associated greenhouse gases. Mixed land uses are promoted, and land policy requires that ground fl oors along main streets be used for commercial applications. This encourages people to walk or cycle to visit streets with lively shop fronts. To attract shops and services to the new development area, the city has provided fi nancial subsidies. Moreover, the area’s economic activities were established in the development’s early phases. Urban and building designs make the most of the waterfront. Myriad designs were created by diff erent architects to provide diverse, lively, and high-quality urban environment.

Stockholm desired that Hammarby Sjöstad be twice as more sustainable than Swedish best practice in 1995 on a range of indicators (the environmental program was adopted in 1995), most notably energy effi ciency per square meter. In Sweden, the average annual rate of energy use in some regular new developments is 200 kilowatt-hours per square meter. Cutting-edge Swedish developments and practices produce an effi ciency of 120 kilowatt-hours per square meter. The Hammarby Sjöstad project aims for 100 kilowatt-hours per square meter. The project also sets other targets: water conservation, waste reduction and reuse, emissions reduction, the reduced use of hazardous construction materials, the application of renewable energy sources, and the implementation of integrated transportation solutions. Stockholm is already a sustainable city, but the city council expects this project to demonstrate additional innovations in sustainable urban development.

The Hammarby Model

The environmental goals for Hammarby Sjöstad, which was originally intended to be the Olympic Village in Stockholm’s bid for the 2004 Summer Olympics, are audacious. The area’s integrated environmental solutions may be understood as an ecocycle known as the Hammarby Model (fi gure 3.21). The ecocycle addresses energy, waste, water, and sewerage for housing, offi ces, and other commercial structures. Core environmental and infrastructure plans for this area have been developed jointly by three city agencies: the Stockholm Water Company, the energy company Fortum, and the Stockholm Waste Management Administration. Project management was spearheaded by a project team comprising representatives from city departments overseeing planning, roads and real estate, water and sewerage, and waste and energy. The project team is housed in the Department of Roads and Real Estate (now called the Development Administration).

The model is an attempt to turn a linear urban metabolism, which consumes infl owing resources and discards outfl owing wastes, into a cyclical system that optimizes the use of resources and minimizes waste. The model

Map 3.4 Master Plan of Hammarby Sjöstad, Stockholm

Source: Stockholm City Planning Administration. Note: For details of the Master Plan, see http://www.hammarbysjostad.se.

streamlines infrastructure and urban service systems and provides a blueprint for achieving sustainability objectives. For instance, it shows the interaction between sewage processing and energy provision, the way refuse should be handled, and the added value to society of modern sewage and waste processing systems. Highlights are as follows:

• Building materials: Environmental considerations apply to all materials, whether used visibly in facades, underground, or internally. This includes structural shells and installed equipment. Only sustainable and tested eco-friendly products are used. Potentially hazardous materials, such as copper and zinc, are avoided to prevent leakages of unwanted substances into the environment.

• Water and sewerage: Storm water is unconnected to sewerage systems to improve the quality of wastewater and sludge. Rainwater from streets or nondomestic storm water is collected, purifi ed through a sand fi lter, and released into the lake. This reduces pressure on the wastewater treatment plant. Rainwater from surrounding houses and gardens fl ows through open drains to the channel.

This water runs through a series of basins, known as an equalizer, and then to the lake.

Hammarby Sjöstad has its own wastewater treatment plant built to test new technology.

Four new and diff erent processes for purifying water are currently being tested.

• Biogas: Biogas is produced in the wastewater plant from the digestion of organic waste and sludge. The wastewater from a single household produces suffi cient biogas for the household’s gas cooker. Most biogas is used as fuel in eco-friendly cars and buses.

• Green spaces: Roofs covered in stonecrop or sedum plants are attractive. In addition, the plants absorb rainwater that would otherwise drain into the sewerage system, adding pressure on the wastewater treatment plant. Moreover, the region’s carefully preserved oak forests, green areas, and other planted trees help collect rainwater instead of draining it into the sewerage system. This vegetation also ensures cleaner air and balances the dense urban landscape.

• Waste: Combustible waste, food waste, newspapers, paper, and other discards are separated and deposited in diff erent refuse chutes in or adjacent to buildings. The refuse chutes are linked to underground vacuum-powered pipes that lead to a central collection station.

An advanced control system sends the waste to large containers, one for each waste category. Refuse collection vehicles thus collect the containers without driving into the area, and refuse collection workers avoid heavy lifting.

• District heating and cooling: Treated wastewater and domestic waste become sources for heating, cooling, and power. A combined heat and power plant uses domestic waste as fuel to produce district heating and electricity. Wastewater from the treatment plant fuels the production of district heating in the Hammarby heat plant. Cooled by heat pumps, the treated and cooled wastewater may also be used in the district cooling network.

• Electricity (solar energy): Solar energy is transformed into electrical energy in solar cells. The energy from a single solar cell module covering one square meter provides around 100 kilowatt-hours per year, which is equivalent to the energy used by three square meters of housing space. There are solar panels on many roofs used to heat water. Solar panels on residential buildings often provide suffi cient energy to meet half of the annual hot water requirements of the buildings.

Hammarby Sjöstad has its own Environmental Information Center, GlashusEtt. This center facilitates communications on environmental considerations to area inhabitants and showcases Hammarby to international visitors.